Rarely disclosure about the asymmetrical hydrogenation reaction of an ∂-ketonic acid compound. In the ligand field, the disclosure of the asymmetrical hydrogenation reaction of an ∂-ketonic acid compound by directly using an metal ligand complex also basically on an vacancy stage. The reasons through analyzing can be concluded as: the carboxyl group on the ∂-ketonic acid compound can coordinate with metal, in that way it will result the catalysts to be poisoned and spoiled, so the reaction yield is lowered. What's more, the two ∂ carbonyl groups one on the ∂-ketonic acid compound and the other on the carboxylic acid are nearly in coplanar position, there will result equal opportunities for chiral ligand catalysts to attack ∂-ketonic acid compound from two sides, of course, leads to lower enantioselectivity and reaction yield.
The following structure chiral spiro-pyridylamidophosphine ligand iridium complex are developed at the earliest by Nankai university.

And it has been disclosed in Chinese application documents with the publication number CN102040625, the chiral spiro-pyridylamidophosphine ligand iridium complex used as a catalyst in the asymmetrical hydrogenation reaction of carbonyl compounds including aryl alkyl ketones, ketenes and keto esters. However, the chiral catalysts actually obtained a little bad catalytic result for keto esters compounds according to its Example 11 table 1 serial number 27.
Considering asymmetrical hydrogenation reaction technology are on an important position and are widely used in organic chemistry, it is necessary to overcome the defects of this technology in the application of ∂-ketonic acid compound. And it is also necessary to improve the asymmetrical hydrogenation reaction technology to form a new technical proposal to finally solve the problem which hardly or difficulty to catalytic ∂-ketonic acid compound.